If you don't want to deal with Windows creation code, you could use GLUT. You can find GLUT here.
That way you can focus on learning OpenGL without having to mess around with the Win32 API. It is pretty straight forward to learn. The famous OpenGL Redbook uses GLUT to provide platform independant code listings.
I have recently been testing algorithms for displaying Isometric tiles in OpenGL using GLUT as the windowing interface which makes setting up a program very quick and easy.
Tutorials can be found here:
Learn how to load 32 Bit TGA files as this can simplify the process of creating transparent portions of a sprite. TGA images can contain a fourth color channel (only in 32 bit mode I believe), which is the alpha channel.
In the fourth channel you usually color the portion of the image you want to be transparent as black and the portion you wish to show through as being white. (So yes, you are using a mask of sorts).
Using the following code in your initialisation function, you tell OpenGL to treat the color white as the portion of the mask that will be visible.
I believe this will only work with lighting disabled however...
glColor4f(1.0f, 1.0f, 1.0f, 1.0f);